Metal-handling method and apparatus



May 6, 1969 F. MULLER 3,442,108

METAL-HANDLING METHOD AND APPARATUS Filed Jan. 20, 1966 Sheet of 4 Inventor; Friedricv MCLLLev 3 A a/mum 4; 420.4 1

Qttovngs May 6, 1969 F. MULLER 3,442,108

METAL-HANDLING METHOD AND APPARATUS 'Filed Jan. 20. 1966 Sheet 3 of 4 Inventor:

Frievic adl May 6, 1969 U R 3,442,108

METAL-HANDLING METHOD AND APPARATUS Filed Jan. 20. 1966 Shee t 2 of 4 In vemor: Friebrbcl (1 CLLLzr 1B blown c M041 Flttomess May 6, 1969 F. MULLER 3,442,108

METAL-HANDLING METHOD AND APPARATUS Filed Jan. 20, 1966 Sheet 4 of 4 Inventor: Frledric? MMLQX 3 Ar Qtcovnegs United States Patent 3,442,108 METAL-HANDLING METHOD AND APPARATUS Friedrich Miiller, Hemer, Germany, assignor to Sundwiger Eisenhutte Maschinenfabrik Grah & Co., Homer-Sundwig, Germany Filed Jan. 20, 1966, Ser. No. 521,897 Claims priority, application Germany, Mar. 23, 1965, S 96,130 Int. Cl. B21d 1/02, 3/02 US. Cl. 72-164 14 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a method and apparatus for handling coiled metal strips, and particularly to a method and apparatus for preventing the appearance of breaks when uncoiling them.

During the uncoiling of annular coils of materials in the form of strips having certain dimensions and degrees of stiffness, so-called coil breaks often occur. The coil breaks, which are generally in the form of kinks or creases, are oriented transversely to the coiling direction of the strip, appear with varying intensity on the strip and are disposed at various distances therealong. Such breaks are obviously undesirable in that they often constitute a major hindrance to further utiization and processing of the strip.

It is already known that an improvement in this situation can be obtained by applying a stronger tractive force to the strip at the point of its uncoiling. The movement of the coil having the form of a series of intermittent, or step-like rotations during the uncoiling of the strip, this stronger force tends to cause a shorter length of strip to be uncoiled during each step, causing the resulting breaks to be less pronounced. The results achieved by this technique, however, have not always proved satisfactory.

Another known technique for reducing the damage to the strip as a result of coil breaks involved supporting the strip at the point of uncoiling by means of a pressure roller about which the strip is curved through an angle of about 90. Although it is true that this technique eliminates the occurrence of coil breaks during the uncoiling of the annular strip, the rolling of the strip around the periphery of the pressure roller gives the strip a new curvature which must be removed in order to yield the desired straight strip, the elimination of this subsequent curvature itself causing coil breaks to occur. However, these coil breaks are closer together and are less pronounced because the pressure roller used is constructed to have as small a diameter as possible and thus give the strip a smaller radius of curvature when passing over this pressure roller.

An additional improvement can be obtained when utilizing this technique, by simultaneously employing a strong tractive force. In such case, the pressure roller is usually supported for construction reasons. This arrangement causes a further decrease to be achieved in the undulations present in the strip because of the shorter lengths of strip uncoiled during each step-like rotation of the coil. However, even when such an improved technique ice is used, the occurrence of coil breaks can not be completely avoided, these breaks being visible as lines or creases extending on the strip surface transversely to the length of the strip.

It is therefore an object of this invention to overcome the above-noted drawbacks.

It is a more specific object of the present invention to eliminate the occurrence of coil breaks during the uncoiling of strips, and particularly metal strips.

A further object of the present invention is to simplify the uncoiling of metal strips.

According to the present invention, these objects are achieved, in an uncoiling device for progressively drawing the strip off of an angular coil, by applying a supporting pressure to the strip at approximately the point where it leaves the coil, by deflecting the strip in a first direc tion transverse to its length for producing a permanent deformation which is approximately equal to the difference between the curvature of the strip when in coiled form and the desired strip curvature, and by then deflecting the strip back in a direction which is opposite to the firstmentioned direction by an amount which is within the elastic limit of the strip.

In further accordance with the present invention, an apparatus is provided for carrying out the above-described method. This apparatus is basically composed of support pressure applyirg means for continuously contacting the strip at approximately the point where it leaves the coil during the entire uncoiling operation, and uncoiling means for deflecting the strip after it: leaves the roller, these uncoiling means being mounted in such a way that a line between the point where the uncoiling means contacts the strip and the point of contact of the pressure applying means against the strip forms an angle with the tangent to the coil strip at the point of contact which remains substantially constant during the uncoiling of the entire strip. Both the support pressure applying means and the uncoiling means are preferably constituted by rollers.

Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a schematic side view of one embodiment of the apparatus of the present invention.

FIGURE 2 is a view simiar to that of FIGURE 1 showing another embodiment of the apparatus of the present invention,

FIGURES 3 to 8 are pictorial diagrams used in explaining the operation of the apparatus of the present invention.

Referring now to FIGURE 1, there is shown an apparatus according to the present invention for uncoiling a coil 2 constituted by a steel strip 3 wound on a spool or drum 1. A pressure roller 4 constituting the support pressure applying means and having a relatively large diameter rests on the outer periphery of the coil 2 and is supported by a roller support bar 6 which is slidably mounted in a cross-head guide 5. The guide is fastened to a stationary frame (not shown) and is oriented to permit the roller to be moved toward and away from the peripheral surface of the coil 2. If the weight of the roller 4 and support bar 6 is not sufficient to provide the required contact pressure, this pressure can be augmented by the provision of a hydraulic driving unit mounted between the guide 5 and the support bar 6. This hydraulic unit is not illustrated inasmuch as it can be constituted by any wellknown, commercially available hydraulic assembly, such as a hydraulic jack. The roller 4 is mounted on a shaft 7 which is connected to one end of a rocker arm 8. The other end of the rocker arm 8 is mounted, through the intermediary of a cross-head guide 11, to be pivotable about the axis of a shaft 9 carrying a supporting roller 10. The shaft 9 is mounted in a stationary support, as is the shaft of drum 1. The rocker arm 8 is also capable of longitudinal move ment with respect to the guide 11. A lever 12 is pivotably mounted at an intermediate point on the rocker arm 8, the lever 12 being lockable with respect to the rocker arm. This lever 12 carries at its free end an uncoiling roller 13 which constitutes the uncoiling means for the device and which acts to aid the uncoiling of the metal strip 3 as it passes from the coil 2 to the supporting roller 10. An additional guide roller 14 for guiding the strip 3 during the uncoilng operation is also supported by rocker arm 8.

The embodiment shown in FIGURE 2 constitutes a modification of the arrangement of FIGURE 1 in that the relative positions of the drum 1 and the pressure roller 4 are interchanged, the pressure roller being mounted on a stationary support and the drum 1 being movably mount ed. In addition, the arrangement of the uncoiling roller 13 is inverted, this roller now resting on the upper surface of the strip 3 and the lever 12 being mounted on a horizontally slidable support element 15 disposed below strip 3. In this embodiment, the guide roller 14 is also disposed below the strip 3 and is mounted on a stationary support (not shown). The device of FIGURE 2 operates in substantially the same manner as that of FIGURE 1.

The uncoiling devices illustrated operate to first bend the strip 3 taken off the coil 2 in such a way as to cause a permanent deformation of the strip and to then bend the strip back in the other direction by an amount which prevents the strip from exceeding its elastic limit, i.e., which prevents the strip from undergoing a further permanent deformation. The first-mentioned bending of the strip produces a permanent deformation which is equal to the difference between the original curvature of the strip when coiled on the drum 1 and the desired final curvature of the uncoiled strip, with allowance being made for acceptable small bending deviations in both directions in the plane of the bending operation.

The first bending of the strip, which causes the desired permanent deformation, is elfectuated by the combined action on strip 3 of rollers 4 and 13. The pressure roller 4 is mounted so as to press continually against the outer periphery of the coil 2 during the entire uncoiling operation. Since the diameter of the coil 2 will decrease prw gresively during the uncoiling operation, a relative movement must take place between roller 4 and drum 1 sub- Stantially in the direction of a line joining the axes of rotation of these two members. This is accomplished, in the embodiment of FIGURE 1, by permitting the support 6 for the roller 4 to slide in the cross-head guide in the direction of the double arrows and in the embodiment of FIGURE 2, by permitting the drum 1 to slide freely in the direction of the double arrows. The pressure roller 4 thus maintains a constant pressure against the strip portion being uncoiled so as to cause the strip to leave the coil 2 in a direction which is substantially tangential to the coil surface. The strip 3 then passes over the uncoiling roller 13, the bending undergone by the strip when passing from roller 4 to roller 13 determining the amount of permanent deformation which will result. To this end, it is necessary, for any given strip material that the position or roller 13 bears a certain relationship to the point of contact between roller 4 and coil 2 and the common tangent plane betwen roller 4 and coil 2. The factors determining this relationship will be discussed in detail below. After having been given the desired curvature by passage between rollers 4 and 13, the strip 3 is bent back by guide roller 14 by an amount which prevents the strip from exceeding its elastic limit. The strip then passes over a second guide roller and is delivered to subsequent stations for carrying out various fabrication processes.

In order to permit the apparatus shown to operate with strips of dilferent materials having varying dimensions, and in order to permit varying degrees of curvature to be given to the uncoiled strip, the uncoiling roller 13 is mounted so that its position with respect to roller 4 and coil 2 can be readily adjusted. Once this position is adjusted for any given strip and any desired curvature, it is necessary that the relative position of roller 13 with respect to roller 4 and coil 2 remains constant during the entire coiling operation, during which the diameter of coil 2 will progresively decrease. To this end, the roller 13 is mounted on a cross arm 8 having one end connected to the shaft 7 of roller 4 and having its other end slidably disposed in a cross-head guide 11 which is itself pivotably mounted on the shaft 9 of roller 10. This arrangement permits cross arm 8 to slide freely in guide 11 and to pivot about the axis of shaft 9 in such a way as to permit roller 4 to move in the direction of the double arrows of FIGURE 1 and to remain constantly in contact with the coil 2 as its diameter decreases, while the roller 13 is also displaced by the movement of cross arm 8. Since roller 4 moves toward the axis of rotation of drum 1, the point of contact between roller 4 and coil 2 will always remain on a line joining the axes of rotation of these two members. Furthermore, during any given uncoiling operation, the distance between the axes of rotation of rollers 4 and 13 will remain constant. As a result, the distance between the point of tangency of strip 3 on roller 13 and the point of contact between roller 4 and coil 2, as well as the displacement of this point of tangency from the common tangent plane between roller 4 and coil 2, will remain substantially constant during the entire uncoiling of coil 2.

A similar result is obtained with the apparatus of FIG- URE 2, wherein the lever 12 is pivoted and the carriage 15 is displaced by the amount necessary to achieve the desired relation between the point of tangency of the strip 3 on roller 13 and the coil 2 and roller 4, the lever 12 and carriage 15 then being locked in position. In this embodiment, the roller 4 is mounted on a stationary support, while the drum .1 is mounted to move in the direction of the double arrows in order to maintain a continuous contact between the periphery of coil 2 and roller 4. The remaining operation of the device of FIGURE 2 is identical to that of FIGURE 1.

All of the various rotating elements of these embodiments are preferably connected to be driven by suitable motors or by a single motor connected to a suitable multiple drive arrangement.

When determining the amount of deflection to be applied to strip 3, account must be taken of the fact that the resilience of the strip material will tend to cause it to return, to some degree, to its original shape after it has been deflected beyond its yield point. As a result, roller 13 must be positioned to deflect strip 3 by a sufiicient amount to cause it to have the desired final curvature when it passes beyond the roller. Based on this consideration, FIGURES 3 to 8 show, in pictorial form, various relative positions of the pressure roller 4 and the uncoiling roller 13 for producing various types of curvatures. FIGURES 3, 5 and 7 show the condition existing at the start of the uncoiling operation, while FIGURES 4, 6 and 8 show the corresponding condition existing near the end of the uncoiling operation, when the drum 1 is almost empty. In these figures it is assumed that the strip 3 is only subjected to the action of rollers 4 and .13, it being assumed that the guide roller 14 is not present. FIGURES 3, 5 and 7 show the distance A between the point of tangency of strip 3 on roller 13 and the point of contact between roller 4 and coil 2 and the displacement f between the point of tangency on roller 13 and a corresponding point on a path 3 having a curvature equal to the desired final curvature of strip 3.

Referring specifically to FIGURES 3 and 4, there is shown the relative position between roller 13 and roller 4 and coil 2 for giving the strip 3 a straight-line configuration, as shown by the dot-dash line 3'.

FIGURES 5 and 6 show an arrangement for giving the strip a large radius of curvature, as shown by line 3', which is larger than, and in the same direction as, the radius of curvature of the strip prior to uncoiling.

Finally, FIGURES 7 and 8 show an arrangement for giving the strip 3 the form represented by the dot-dash line 3', in which the strip has a relatively large radius of curvature which is in the opposite direction from the radius of curvature of the coil 2.

As may be seen from FIGURES 3 through 8, the radius of curvature of the uncoiled strip 3 can be varied over a wide range by varying the displacement of the point of tangency of the strip on the roller 13- from the common tangent plane T of roller 4 and coil 2. However, because of the above-noted resilience of strip materials, it is necessary to bend the strip by a sufficient amount to cause it to have the desired degree of curvature after it passes beyond roller 13 and deflects slightly back toward its previous configuration. For example, if it were desired to produce a straight strip, as shown by the dot-dash line 3 of FIGURES 3 and 4, it would be necessary to place the roller 13 in the position shown in these figures so that the point of tangency of the strip 3 or roller 13 is displaced from the final position desired for this point on the strip by the distance f. The same is true for the curvatures illustrated in FIGURES 5 through 8. The magnitude of this transversedisplacement of the point of tangency on roller 13 is given by the equation:

I II Yield point 6 F (kn/mm?) 21 44 Modulus of elasticity E (kp./mm. 21, 000 22, 000 Thickness h (mm.) 10 3 Roller spacing A (mm.) 600 300 Insertion of the values given for the two examples above in the previously-cited equation yields as the value of 24 mm. for Example I and 40 mm. for Example II. These values represent the displacement J of the point of tangency on roller 13 in a transverse direction with respect to the line which would be followed by a strip leaving the coil 2 and having the desired final curvature. Thus, these distances apply equally well to any desired final radius of curvature for the uncoiled strip 3. The manner of construction of the embodiments of FIGURES 1 and 2 ensures that this distance will remain constant during the uncoiling of the entire coil 2.

In practice, this displacement need not be determined by calculation, but rather by estimation because the final curvature of the strip need not normally be precise. It is only necessary, in order to avoid the creation of coil breaks, i.e., kinks or folds transverse to the length of the strip, that the curvature produced by the bending operation be approximately equal to the desired final curvature so that, after the strip has left roller 13, any further deformation thereof wll not cause the proportional limit, or elastic limit, of the strip to be exceeded.

In the apparatus of FIGURES 1 and 2, the position of the various adjustable rollers can be controlled in any known manual, mechanical, hydraulic, pneumatic, or electrical manner. Furthermore, the beginning of the uncoiling operation can be facilitated by moving the uncoiling roller rapidly away from the pressure roller to assist feeding the strip 3 over roller 13, for the device of FIGURE 1, or under this roller, for the device of FIGURE 2.

It may thus be seen that the present invention provides a novel arrangement for avoiding the formation of kinks or folds during the uncoiling of a coiled strip wherein the distance between the points at which the strip is supported while it is being deformed is smaller than the theoretical spacing between these kinks or folds, which are known as coil breaks. Thus, the novel method and apparatus of the present invention permit a complete elimination of such coil breaks, a result which was not obtainable with any of the prior art methods or apparatus.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

1. A method for preventing the occurrence of coil breaks while uncoiling an annularly coiled strip, compris ing the steps of:

(a) applying a supporting pressure transversely to the strip against the coil at approximately the point where the strip leaves the coil; and

(b) deflecting the strip as it leaves the coil in a direction to effectuate its uncoiling for producing a permanent deformation of the strip, which deformation is approximately equal to the difference between the curvature of the coiled strip and the desired strip curvature.

2. A method as defined in claim 1 wherein the deflecting of the strip is carried out by applying a force to the strip at a point whose distance from the point at which the supporting pressure is applied is less than the theoretical spacing between coil breaks.

3. A device for uncoiling a strip originally formed in a coil while preventing the occurrence of coil breaks therein, comprising in combination.

(a) support pressure applying means for continuously contacting the strip at approximately the point where it leaves the coil during the entire uncoiling operation; and

(b) means for deflecting the strip as it leaves the coil and being mounted for causing the line between the point Where it contacts the strip and the point of contact of said pressure applying means to form an angle with the tangent to the coiled strip at said point of contact which remains substantially constant during the uncoiling of the entire strip.

4. An arrangement as defined in claim 3 wherein said supporting pressure applying means is constituted by a vertically adjustable pressure roller and said means for deflecting the strip, is constituted by an uncoiling roller.

5. An arrangement as defined in claim 4 wherein said uncoiling roller is mounted to have its position selectively varied with respect to the position of said pressure roller.

6. An arrangement as defined in claim 5 wherein the position of said uncoiling roller can be varied in directions substantially both parallel and perpendicular to the longitudinal dimension of the uncoiled strip.

7. An arrangement as defined in claim 4 wherein both of said rollers are mounted to be motor-driven.

8. An arrangement as defined in claim 4 further comprising: a cross-head guide supporting said pressure roller for permitting said pressure roller to move transversely to the surface of the coil; a rocker arm having one end connected to said pressure roller and having its other end mounted to pivot about a stationary axis and to permit said arm to move in a longitudinal direction; and a lever having one end pivota'bly connected to said rocker arm and its other end supporting said uncoiling roller.

9. An arrangement as defined in claim 8 wherein all of said rollers are mounted to have their positions selectively varied.

10. An arrangement as defined in claim 4 further comprising a guide roller for guiding the strip after it leaves said uncoiling roller.

11. An arrangement as defined in claim 4 whereby said uncoiling roller can be rapidly moved away from said pressure roller to assist urging the strip into position on said uncoiling means at the beginning of the uncoiling operation.

12. An apparatus for preventing the occurrence of coil breaks while uncoiling an annularly coiled strip, comprising:

(a) means for applying a supporting pressure transversely to the strip against the coil at approximately the point where the strip leaves the coil; and

(b) means for deflecting the strip as it leaves the coil in a direction to efiectuate its uncoiling for producing a permanent deformation of the strip, which deformation is approximately equal to the difference between the curvature of the coiled strip and the desired strip curvature.

13. A method as defined in claim 1 comprising the sub- 8 sequent step of deflecting the strip back in a direction which is opposite to the uncoiling direction by an amount which is within the elastic limit of the strip.

14. An arrangement as defined in claim 12 further comprising means deflecting the strip back in a direction which is opposite to the uncoiling direction by an amount which is within the elastic limit of the strip.

References Cited UNITED STATES PATENTS 2,087,010 7/1937 Wardle et al. 72-l65 3,079,976 3/1963 Ranney 72-183 RONALD D. GREFE, Primary Examiner.

US. Cl. X.R. 72-183 

